Ta có : \(x=x_0+v_0t+\frac{1}{2}at^2\)
Mà \(\left\{{}\begin{matrix}x_0=0\left(m\right)\\v_0=0\left(m/s\right)\end{matrix}\right.\)
=> \(x=\frac{1}{2}at^2=\frac{1}{2}.a.100^2=20\left(m\right)\)
=> \(a=0,004\left(m/s^2\right)\)
\(a=\frac{\Delta s}{\Delta t}=\frac{20-0}{100-0}=0,2\)(m/s2)